1. Field of the Invention
This invention relates to the construction of reinforced concrete walls, in particular curved walls such as those of above-ground silos or in-ground tanks or the like.
2. Description of the Prior Art
Such walls are conventionally constructed with the aid of a slip-form which defines at least the inner surface of a wall-space into which the concrete is poured, and which is raised progressively as the poured concrete hardens. The slip-form also supports a working platform for the operators, who position reinforcing and pour the concrete.
As a general rule the reinforcing in such walls is a structure comprising an array of vertical rods and an array of horizontal rings of rods spaced one above the other and secured to the vertical rods. Often there are two such structures, one disposed adjacent the inner surface of the wall and the other disposed near the outer surface of the wall.
The slip-form as a whole is normally supported by a plurality of yokes extending upwards and into the wall space to engage jacks usually secured to or operating on previously emplaced vertical rods. The slip-form may be raised by those jacks as the wall is built.
Thus, whereas the vertical rods may be readily enough lowered into position by a crane the horizontal rods are more difficult to position since the yokes encroach into the wall-space and prevent them from being lowered into place while they are horizontal.
Of course, the slip-form could be raised by means which do not attach to yokes. In which case any other upwardly extending support or guide members, such as those required to support the formwork or prevent lateral movement of the slip-form as it is raised may be utilized in the invention to provide a mechanism which assists in positioning the horizontal reinforcement rods.
Hitherto the horizontal rods have been man-handled into position by a gang of men standing on the working platform.